US8287602B2 - Urinary stent - Google Patents

Abstract

A urinary stent includes an elongate member that defines a lumen extending therethrough and that is configured to be disposed at least partially within a prostatic portion of a urethra of a patient. The elongate member includes a collapsible portion disposed at a proximal end portion of the elongate member. The collapsible portion has a first configuration in which an outer perimeter at a proximal end of the collapsible portion is substantially equal to an outer perimeter of a remaining portion of the elongate member and a second configuration in which the outer perimeter at the proximal end of the collapsible portion is smaller than the outer perimeter of the remaining portion of the elongate member.

Description

CROSS-REFERENCE TO RELATED CASES

This application claims priority to, and the benefit of Provisional U.S. Patent Application Ser. No. 61/013,034, filed Dec. 12, 2007, the entirety of which is incorporated herein by reference.

TECHNICAL FIELD

The invention relates generally to medical devices and more particularly to a urinary stent. The stent can allow fluid drainage from a bladder and through a urethra of a patient.

BACKGROUND INFORMATION

The male urethra is generally a tubular passageway extending from the bladder to the end of the penis. As urine travels from the bladder and out of the body, the urine passes through four sections of the urethra referred to as the prostatic urethra, the membranous urethra, the bulbar or bulbous urethra, and the pendulous or distal urethra. Surrounding the prostatic urethra and below the bladder is a prostate gland. In some men, especially men over fifty years of age, the prostate can become swollen or enlarged due to disease or infection. The enlarged prostate can constrict the urethra causing discomfort and/or bladder outlet obstruction.

Medical devices, such as urethral stents, are typically used to facilitate fluid flow from a bladder and through a urethra. Urethral stents are designed to hold open one or more of the sections of the urethra obstructing the flow of urine, such as constricted portions caused by a swollen or enlarged prostate. The size or outer perimeter of a stent that is needed to maintain the urethra in an open state can sometimes result in difficulty removing the stent from the patient's body.

SUMMARY OF THE INVENTION

The invention relates generally to a urinary stent, such as a male urethral stent, for at least partial placement in a prostate portion of a urethra of a patient, and the stent includes a removal mechanism to allow the stent to be removed easily from the urethra of the patient.

In one aspect, the invention involves a urinary stent that includes an elongate member that defines a lumen extending therethrough and that is configured to be disposed at least partially within a prostatic portion of a urethra of a patient. The elongate member includes a collapsible portion disposed at a proximal end portion of the elongate member. The collapsible portion has a first configuration in which an outer perimeter at a proximal end of the collapsible portion is substantially equal to an outer perimeter of a remaining portion of the elongate member. The collapsible portion has a second configuration in which the outer perimeter at the proximal end of the collapsible portion is smaller than the outer perimeter of the remaining portion of the elongate member.

Embodiments according to this aspect of the invention can include the following features. The collapsible portion can be frusto-conical in shape when in the second configuration. The collapsible portion can be formed monolithically with the elongate member. The collapsible portion can define an opening at a proximal end of the collapsible portion, and the opening can have a first diameter in the first configuration and a second smaller diameter in the second configuration. The collapsible portion can include a first arm and a second arm, where the first arm and the second arm each define an opening at a proximal end of the collapsible portion. In some embodiments, the urinary stent can further include a second portion that extends from the elongate member opposite the collapsible portion and that is configured to be disposed at least partially within a bladder of the patient.

In another aspect, the invention involves a urinary stent that includes an elongate member defining a lumen extending therethrough and that is configured to be disposed at least partially within a prostatic portion of a urethra of a patient. The elongate member includes a collapsible portion disposed at a proximal end portion of the elongate member. The collapsible portion defines an opening at a proximal end of the collapsible portion in communication with the lumen and has a first configuration in which the opening is substantially open. The collapsible portion has a second configuration in which the collapsible portion is at least partially collapsed and the opening is at least partially closed such that at least part of the collapsible portion is smaller at its outer perimeter than an outer perimeter of the rest of the elongate member. The urinary stent also includes a second portion extending from the elongate member opposite the collapsible portion and that is configured to be disposed at least partially within a bladder of the patient.

Embodiments according to this aspect of the invention can include the following features. The collapsible portion can be frusto-conical in shape when in the second configuration. The collapsible portion can be formed monolithically with the elongate member. The opening can have a first diameter in the first configuration and a second smaller diameter in the second configuration. The collapsible portion can include a first arm and a second arm, and the first arm and the second arm define the opening. The second portion can have a collapsed configuration for insertion into the bladder, and an expanded configuration for retaining the second portion within the bladder.

In yet another aspect, the invention involves a urinary stent that includes an elongate member that defines a lumen extending between a proximal end and a distal end of the elongate member. The elongate member is configured to be disposed at least partially within a prostatic portion of a urethra of a patient and includes a tapered proximal end portion that defines an opening on a proximal end of the elongate member. The opening is in communication with the lumen of the elongate member to facilitate fluid flow therethrough. A second portion extends from the elongate member opposite the tapered, proximal end portion and is configured to be disposed at least partially within a bladder of the patient.

Embodiments according to this aspect of the invention can include the following features. The second portion can be coupled to the elongate member. The tapered proximal end portion can be formed monolithically with the elongate member. The tapered proximal end portion can be frusto-conical in shape and define the opening as a substantially fixed size opening. The second portion can have a collapsed configuration for insertion into the bladder and an expanded configuration for retaining the second portion within the bladder. The urinary stent can further include a tether coupled to the tapered proximal end portion, and the tether extends proximal from the elongate member.

For a fuller understanding of the nature and operation of various embodiments according to the invention, reference is made to the drawings briefly described in next section and also to the more detailed description that follows the brief description of the drawings. The drawings should be considered in conjunction with the following more detailed description. In the drawings, the same or similar reference numbers generally denote the same or similar elements of the various disclosed embodiments. The drawings are not necessarily to scale, emphasis instead generally being placed on conveying certain concepts and aspects according to the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of an embodiment of a delivery device and implant.

FIG. 2 is a side perspective view of a stent according to an embodiment of the invention shown with a proximal end portion in an expanded configuration.

FIG. 3 is a side perspective view of the stent ofFIG. 2, shown with the proximal end portion in a collapsed configuration.

FIG. 4 is a proximal end view of the stent ofFIG. 2 taken along line4-4 inFIG. 2.

FIG. 5 is a proximal end view of the stent ofFIG. 3 taken along line5-5 inFIG. 3.

FIG. 6 is a side view of a pushing device according to one embodiment.

FIG. 7 is a side perspective view of the stent ofFIG. 2 shown with the pushing device ofFIG. 6 disposed therein.

FIG. 8 is a side view of the stent ofFIGS. 2-5 shown in a collapsed configuration and being inserted through a schematic illustration of a male urinary system.

FIG. 9 is a side view of the stent ofFIGS. 2-5 shown in an expanded configuration and inserted within a male urinary system.

FIG. 10 is a side perspective view of a stent according to another embodiment of the invention.

FIG. 11 is a side view of a stent according to another embodiment of the invention.

FIG. 12 is a distal end view of the stent ofFIG. 11.

FIG. 13 is a side view of a stent according to another embodiment of the invention.

DESCRIPTION

The medical devices and methods described herein are generally directed to a urinary stent that can be at least partially inserted into a prostatic portion of male urethra. The stents include a removal feature or mechanism to allow for easy removal of the stent from a urethra of a patient. For example, in one embodiment, a stent includes a collapsible proximal end portion that can be biased into an expanded configuration while disposed within a prostatic urethra, and then moved to a collapsed configuration for removal of the stent from the urethra of the patient. In another embodiment, a stent includes a tapered proximal end portion with a generally fixed tapered shape that is not designed to be collapsed in the same manner as the former embodiment. With both embodiments, the a smaller leading proximal end is realized and allows for easy removal of the stent from the urethra of the patient.

The terms proximal and distal require a point of reference. In this application, the point of reference is the perspective of the operator (e.g., surgeon, physician, nurse, technician, etc.) who would insert the disclosed medical device into the patient. Therefore, the term proximal will always refer to an area closest to the operator, whereas distal will always refer to an area away from the operator. The end of the stent inserted first inside a patient's body would be the distal end of the stent, and the end of the stent closest to the operator and to an exterior incision or opening in the patient's body would be the proximal end of the stent. The patient can be a male human or some other mammal.

As mentioned above, in one embodiment according to the invention, a urinary stent includes an elongate member that defines a lumen extending therethrough and is configured to be disposed at least partially within a prostatic portion of a urethra of a patient. The elongate member includes a collapsible portion disposed at a proximal end portion of the elongate member. The collapsible portion has a first configuration in which an outer perimeter at a proximal end of the collapsible portion is substantially equal to an outer perimeter of a remaining portion of the elongate member. The collapsible portion also has a second configuration in which the outer perimeter at the proximal end of the collapsible portion is smaller than the outer perimeter of the remaining portion of the elongate member.

In this first embodiment, the collapsible portion of the elongate member can define an opening at the proximal end of the collapsible portion, where the opening is in communication with the lumen defined by the elongate member. The opening will be substantially open when the collapsible portion is in the first configuration, and the opening will be at least partially closed when the collapsible portion is in the second configuration. Also, a second portion of the urinary stent can extend from the elongate member of the stent opposite the collapsible portion of the stent's elongate member, and this second portion can be configured to be disposed at least partially within a bladder of the patient.

In a second embodiment according to the invention, a tapered proximal end portion is used in place of the first embodiment's collapsible portion. That is, in the second embodiment, the elongate member of the urinary stent includes a tapered proximal end portion that defines a fixed opening. This opening is in communication with the lumen of the elongate member to facilitate fluid flow therethrough. A second portion can extend from the elongate member opposite the tapered proximal end portion, and this second portion can be configured to be disposed at least partially within a bladder of the patient.

The use of stents or other types of endoluminal mechanical support devices to keep a duct, vessel or other body lumen open is one type of therapy for treating lumen stenosis or lumen obstruction. To treat lumen stenosis either a permanent or temporary stent can be used. A permanent stent is typically disposed within a body lumen for an indeterminate time period. A temporary stent is typically used to hold a body lumen open for a limited period of time to maintain the patency of the lumen, for example, after trauma to a lumen caused by a surgical procedure or injury.

A prostatic stent is a temporary stent in that it is typically used to keep the prostatic lobes apart, preventing the compression of the urethra and allowing the flow of fluid (e.g., urine) therethrough. For example, a prostatic stent may be desired after different types of prostatic thermal therapy methods such as, for example, Visual Laser Ablation of the Prostate (VLAP), Transurethral Microwave Thermotherapy (TUMT), Transurethral Ultrasound-Guided Laser Incision of the Prostate (TULIP), Interstitial Laser Coagulation (ILC), Transurethral Needle Ablation (TUNA), HIFY, cryosurgery, etc., to treat benign prostatic hyperplasia. Such stents can also be used in provisional treatment of patients with urinary retention prior to prostatic surgery, or to test the effect of surgical treatment in the case of lower urinary tract obstruction induced by benign prostatic hyperplasia. As the oedema (i.e., build up of excess fluid) subsides, the stent can be withdrawn. Typical removal procedures include the pulling of a suture or tether coupled to the stent. Stents and methods to remove such stents are described herein that reduce or eliminate discomfort to the patient during the removal process.

FIG. 1 is a schematic illustration of a urinary stent (also referred to herein as “prostatic stent” or “stent” or “urethral stent”, for example) according to an embodiment of the invention shown disposed within a schematic illustration of a male urinary system. The anatomy of the male urinary system shown inFIG. 1 includes a urethra50 (also referred to herein as “penile urethra”), an external sphincter52, an opening to theexternal sphincter54, a prostate56, a prostatic section of the urethra58 (also referred to herein as “prostatic urethra”), abladder neck sphincter60 and abladder62. The point of insertion of a prostatic stent is through themeatus64.

A prostatic stent20 includes anelongate member22 that is sized to be at least partially disposed within theprostatic urethra58. For example, theelongate member22 can have an outer perimeter sized to maintain theprostatic urethra58 in an open state. Theelongate member22 defines a lumen (not shown) extending between a proximal end and a distal end of theelongate member22 to facilitate fluid (e.g., urine) flow therethrough. Theelongate member22 can be a variety of different configurations. For example, theelongate member22 can be coiled or have an accordion shape. Theelongate member22 can also be formed with a flexible material to allow it to accommodate bodily movements.

Theelongate member22 also includes a proximal end portion24 that can be used to provide easy removal of the stent20 from the prostatic urethra and urethra. For example, the proximal end portion24 can be shaped to provide for a tapered removal end. In some embodiments, the proximal end portion24 can be moved from a first configuration in which the proximal end portion24 has a an outer perimeter substantially the same as an outer perimeter of a remaining portion of theelongate member22, to a second configuration in which the proximal end portion24 has an outer perimeter smaller than the outer perimeter of the remaining portion of theelongate member22. The proximal end portion24 can be formed monolithically with theelongate member22, or can be a separate component coupled to theelongate member22. The various embodiments of the proximal end portion24 are described in more detail below with reference to specific embodiments.

Atether32, such as a suture, is coupled to the proximal end portion24 and extends out through theurethra50. Thetether32 can be used to urge the stent20 proximally for removal of the stent20 from the patient's body. Abead member34 can be coupled to thetether32 as shown inFIG. 1. Thebead member34 can prevent a proximal end portion of thetether32 from being pulled distally into theurethra50. Thebead member34 can be a variety of different shapes and sizes and can, in some embodiments, be slidably coupled to thetether32.

The prostatic stent20 also includes a retaining member28 extending distally from theelongate member22, and a distal tip portion30. As with the proximal end portion24, the retaining member28 can be formed monolithically with theelongate member22, or be a separate component coupled to theelongate member22. Likewise, the distal tip portion30 can be formed monolithically with the retaining member28 or provided as a separate component coupled thereto. The retaining member28 is configured to be disposed within thebladder62 and prevent theelongate member22 from being moved proximally out of theprostatic urethra58. For example, fluid pressure within thebladder62 andprostatic urethra58 can exert pressure on theelongate member22 urging it proximally. The retaining member28 can be a variety of different shapes, sizes and configurations. For example, possible embodiments of a retaining member include umbrella shaped prongs and a pigtail curl. Retaining member embodiments are typically at least partially collapsible or able to be straightened for insertion into a body lumen.

In some embodiments, a retaining member is not required, for example, if a prostatic stent includes another means to prevent migration of the prostatic stent from the prostatic section of the urethra (for example, an elongate member that frictionally engages the patient's prostate section of the urethra). The distal tip portion30 is also configured to be disposed within the bladder30. The distal tip30 can be shaped and/or sized to help insert the stent within the urinary system. For example, the distal tip30 can be tapered from a proximal end to a distal end of the distal tip30. The distal tip30 can also be curved or have a coude shape.

Having described above various general examples, several examples of specific embodiments are now described. These embodiments are only examples, and many other configurations of a stent20 are contemplated.

FIGS. 2-5 illustrate a prostatic stent according to a first embodiment of the invention. Aurinary stent120 includes anelongate member122, a retainingmember128, and adistal tip portion130. Theelongate member122 defines a lumen144 (seeFIGS. 4 and 5) that extends from aproximal end138 to adistal end146 to facilitate the flow of fluid therethrough. In this embodiment, the retainingmember128 has a collapsed configuration for insertion of thestent120 into, for example, a urethra, and an expanded configuration to anchor or retain thestent120 in position within the urethra. For example, the retainingmember128 can be pre-set or biased into the expanded configuration and moved to the collapsed configuration with use of, for example, a pusher device (shown inFIG. 6). Thedistal tip portion130 is curved to help with insertion and maneuvering thestent120 through a urinary system (e.g., through a urethra and into a bladder). Thedistal tip portion130 also defines anopening148 and a lumen (not shown) extending therethrough.

The retainingmember128 can be collapsed prior to insertion into a urethra using a pusher device as mentioned above, or with the use of other known actuating devices. For example, a pusher device can be inserted through the lumen144 of theelongate member122, through an interior region defined by the retainingmember128, and into the lumen of thedistal tip portion130. The pusher device can be used to collapse the retainingmember128 by applying a distal force with the pusher device as described in more detail below.

Theelongate member122 can be formed with a flexible material and have an accordion-type configuration, as shown inFIGS. 2 and 3, to allow theelongate member122 to be easily maneuverable within a urethra and to accommodate for bodily movements. Theelongate member122 includes aproximal end portion124 that includes a pair ofarms140 and142 that collectively define anopening136 at theproximal end138 of theelongate member122. Although two arms are shown, in alternative embodiments, theproximal end portion124 can include more than two arms.

Theproximal end portion124 has an expanded or open configuration, as shown inFIGS. 2 and 4, and a collapsed or substantially closed configuration, as shown inFIGS. 3 and 5. For example, thearms140 and142 can be formed with a shape-memory material and biased into the expanded configuration. Thearms140 and142 can then be moved to the collapsed configuration by urging thearms140 and142 toward each other. Atether132 is coupled to each of thearms140 and142 and used to urge thearms140 and142 toward each other.

When theproximal end portion124 is in the expanded configuration, theopening136 defined by thearms140 and142 is a first size or diameter as shown inFIG. 4. When theproximal end portion124 is in the collapsed configuration, theopening136 defined by thearms140 and142 is a second size or diameter that is smaller than the first size of theopening136, and theproximal end portion124 forms a frusto-conical shape, as shown inFIGS. 3 and 5. Also shown inFIGS. 4 and 5, when theproximal end portion124 is in the expanded configuration (FIG. 4), an outer perimeter P1 at theproximal end138 is greater than an outer perimeter P2 at theproximal end138 when theproximal end portion124 is in the collapsed configuration (FIG. 5). The outer perimeter P1 is substantially equal to an outer perimeter of the remaining portion of theelongate member122. While thestent120 is disposed within a urinary system of a patient, theproximal end portion124 maintains the expanded configuration to hold open the prostatic urethra and allow for fluid flow through theelongate member122 and urethra. The smaller outer perimeter P2 of theproximal end portion124 in the collapsed configuration provides a lower profile configuration to assist with the removal of thestent120 from the prostatic urethra and urethra.

As stated above, prior to insertion of thestent120 into a male urinary system of a patient, the retainingmember128 is moved to the collapsed configuration using, for example, a pushingdevice166, as shown inFIGS. 6 and 7.FIG. 6 is a side view of a pushingdevice166, andFIG. 7 is a side view of thestent120 with the retainingmember128 collapsed using the pushingdevice166. To collapse the retainingmember128 using the pushingdevice166, a physician can hold thetether132 while applying a force in a distal direction (e.g., in a direction of arrow A shown inFIG. 7).

The pushingdevice166 includes ahandle168, and has adistal end170 and aproximal end172. A width of the pushingdevice166 is sized to fit within the lumens of the prostatic stent120 (e.g., within the lumen of theelongate member122, the interior region of the retainingmember128 and the lumen of the distal tip portion130). A length of the pushingdevice166 is sized so that thedistal end170 can contact an interior wall of adistal end178 of thedistal tip portion130, while theproximal end172 and handle168 extend outside of the patient's body. The pushingdevice166 can be made from any material that is flexible enough to conform to the patient's anatomy, but also rigid enough to extend thedistal tip portion130 away from theelongate member122. Materials such as stainless steel or polycarbonate meet these criteria.

The pushingdevice166 can be curved, as shown inFIG. 6, or straight (not shown), to accommodate the particular configuration of thestent120 and to aid in the insertion and placement of theprostatic stent120 within the prostatic portion of the urethra. In some embodiments, the pushingdevice166 can include a lumen extending through the pushingdevice166 capable of receiving a guide wire. Theproximal end172 of the pushingdevice166 is coupled to thehandle168.

FIGS. 8 and 9 illustrate the insertion of thestent120 into a male urinary system using the pushingdevice166. As illustrated inFIG. 8, with the retainingmember128 in the collapsed configuration, the physician inserts thestent120 through themeatus164. As stated above, to maintain the retainingmember128 in the collapsed configuration, the physician holds thetether132 while applying a distal force to the pushingdevice166. Thestent120 is advanced through theurethra150 until thedistal tip portion130 and retainingmember128 are positioned within thebladder162, and theelongate member122 is positioned at least partially within theprostatic urethra158. As thestent120 is being inserted through theurethra150, theproximal end portion124 will be partially collapsed due to the pulling on thetether132 during insertion of thestent120. After being properly placed within the urinary system, the physician can release thetether132 and remove the pushingdevice166. This will allow the retainingmember128 and theproximal end portion124 to each be moved back to their respective biased expanded configurations, as shown inFIG. 9.

Theprostatic stent120 can remain inside the male urinary system to prevent bladder outlet obstruction and to promote prostate recovery. With thestent120 disposed within theexternal sphincter opening154 will contract, allowing theexternal sphincter152 to operate normally and thus allowing the patient to control bladder functions even though theprostatic stent120 remains in place. Thetether132 attached to theproximal end portion124 extends through theurethra150 and terminates just outside themeatus164, or can alternatively have a length sized to terminate within theurethra150, just inside themeatus164. Thetether132 is thin enough to pass through the contractedexternal sphincter opening154 without negatively impacting the operation of theexternal sphincter152, or therefore the patient's bladder control.

To remove thestent120 from the urinary system (for example, at a later time), the physician can pull proximally on thetether132. This action will cause thearms140 and142 of theproximal end portion124 to be urged toward each other, and move theproximal end portion124 to its collapsed configuration (as shown inFIGS. 3 and 5). As the stent is pulled proximally, the retainingmember128 will at least partially collapse as it is pulled through the bladder neck sphincter160,prostatic urethra158 andurethra150 due to lateral forces on the retainingmember128. The physician continues to pull on thetether132 until thestent120 is removed from the patient's body.

In some embodiments, prior to removing thestent120 from the patient, the pushingdevice166 can optionally be inserted back into thestent120 to move the retainingmember128 back to its collapsed configuration. In such a case, while holding thetether132, the physician can insert the pushingdevice166 into thestent120, moving the retainingmember128 to its collapsed configuration. The physician can then pull thetether132 and pushingmember166 proximally to remove both from the patient.

In some embodiments, a guide wire (not shown) can be used to assist in guiding the stent through the urinary system. For example, a stent (as described herein) can optionally include an opening on a distal end through which a guide wire can be inserted. In such embodiments, the pushing device used to insert the stent can also include a lumen extending therethrough, and an opening on a distal end. The guide wire can be inserted through a urethra and into a bladder of a patient. The pushing device can then be used as described above to move a retaining member of the stent to a collapsed configuration. After the guide wire is in position within the urinary system, the stent (with the pushing device disposed therethrough) can be inserted into the urethra and advanced into the bladder using the guide wire as a guide to assist in placement of the stent. For example, the lumen of the pushing device can be distally moved over the guide wire. After the stent is positioned in a desired location, the guide wire and pushing device are removed. The guide wire can alternatively be placed through the lumen of the pushing device prior to inserting the guide wire into the urinary system.

In some embodiments, a delivery sheath (not shown) can be used in conjunction with a pushing device to place thestent120 within a male urinary system. In such an embodiment, the sheath can be placed over theelongate member122 andtether132 such that a distal end of the sheath contacts a proximal end of the retainingmember128. The sheath can be used to push thestent120 distally through the urethra. Once thestent120 is properly placed, with the retainingmember128 disposed within the bladder and theelongate member122 at least partially disposed within the prostatic portion of the urethra, the sheath can be removed along with the pushing device.

A second disclosed embodiment of a prostatic stent having a proximal end portion configured for easy removal of the stent is illustrated inFIG. 10. In this second embodiment, aurinary stent220 is similarly constructed as the previous/first disclosed embodiment, and can be positioned within a male urinary system in a similar manner. Thestent220 includes anelongate member222 that defines a lumen (not shown inFIG. 10) that extends therethrough and anopening236 at aproximal end138 of theelongate member222. Theelongate member222 includes aproximal end portion224 that tapers toward aproximal end238 of theelongate member222. The taperedproximal end portion224 provides a relatively small profile leading edge for easier removal of thestent220 from a urethra of the patient in a similar manner as described above. The shape of the taperedproximal end portion224 can be frusto-conical. Atether232 can be coupled to theproximal end portion224 and used to pull thestent220 proximally out of the patient's body.

FIG. 11 illustrates a stent according to an embodiment of the invention that does not include a collapsible retaining member (e.g.,128,228) for placement in at least part of the bladder of the patient. Instead of the retaining member, in this alternative embodiment, astent320 includes anelongate member322 that is sized to frictionally engage a prostatic portion of a urethra to retain theelongate member322 in position within the prostatic urethra. Theelongate member322 defines a lumen344 extending between aproximal end338 and adistal end346, andopenings336, and374 on theproximal end338 anddistal end346, respectively. Theelongate member322 also includes aproximal end portion324 havingcollapsible arms340 and342 similar to theproximal end portion124 described above. This stent ofFIG. 11 is a variation of the first disclosed embodiment of a urinary stent according to the invention that has a collapsible proximal end portion that allows easy removal of the stent from the patient.

In this embodiment shown inFIG. 11, thestent320 can be inserted into a urinary system using a pushing device (not shown) that includes a radially extending flange at a distal end. When the pushing device is inserted through the lumen344 of theelongate member322, the flange of the pushing device engages a corresponding flange374 (seeFIG. 12) on thedistal end346 of theelongate member322 to push thestent320 distally through a urethra. Atether332 coupled to theproximal end portion324 is used to collapse theproximal end portion324 as described above with reference tostent120, to remove thestent320 from the patient.

FIG. 13 illustrates a stent similar to the second disclosedembodiment stent220 ofFIG. 10, except with anopening476 at a distal end for receiving a guide wire therethrough. Thestent420 includes anelongate member422 and acollapsible retaining member428. Theelongate member422 has a proximal end portion424 that is tapered toward aproximal end438 of theelongate member422, and defines anopening438. Atether432 is coupled to the proximal end portion424 and used for removal of thestent420 as described above for previous embodiments. In this embodiment, abead member434 is also coupled to thetether432.

The two main disclosed embodiments of urinary stents according to the invention (referred to and shown here generally as120 and220), as well as the other disclosed embodiments (e.g.,20,320, and420) can be constructed with any suitable material used for such medical devices. For example, the various components of a stent can be formed with one or more biocompatible materials, such as silicone, nylon, polyglycolic acid, or stainless steel, and various polymers. The various components of a stent according to the invention can be formed with various elastic materials, flexible materials, rubber materials, or combinations thereof. In addition, various components, such as the collapsible portion (e.g.,124,324) and the retaining member (e.g.,128,228,428) can each be formed with a shape-memory material such as nitinol or super-nitinol, where nitinol is a trademark standing for a nickel-titanium alloy material.

All disclosed embodiments are examples and are not limiting or restrictive on the invention. Also, while certain embodiments and related methods have been particularly shown and described, various changes in form and details may be made and are included herein. For example, the collapsible portion and the retaining member can each be moved between their collapsed and expanded configurations by means other than those described herein such as by hinges or other mechanisms. Also, various different types of delivery devices can be used to insert and/or remove a urinary stent into/from the body of a patient. Further, the distal tip portion, the retaining member, the elongate member, and the collapsible portion can have a variety of different shapes and sizes. A retaining member can be, for example, an expandable balloon or other type of expandable member configured to maintain the elongate member in position within a urinary system.

Claims (10)

1. A urinary stent comprising an elongate member, the elongate member defining a lumen extending from a proximal end to a distal end of the elongate member, the proximal end comprising a proximal tip configured to be disposed within a prostatic portion of a urethra of a patient, the proximal end comprising a first arm and a second arm disposed opposite the first arm, the first and second arms defining an opening at the proximal tip of the proximal end, the first and second arms being biased in an expanded configuration in which the opening has a diameter that is substantially equal to an outer diameter of a remaining portion of the elongate member, and movable into a collapsed configuration in which the diameter of the opening is smaller than the outer diameter of the remaining portion of the elongate member.

2. The urinary stent ofclaim 1 wherein the collapsed configuration forms a frusto-conical shape terminating at the proximal tip of the proximal end of the elongate member.

3. The urinary stent ofclaim 1 wherein the first and second arms are formed monolithically with the elongate member.

4. The urinary stent ofclaim 1 further comprising a second portion extending from the distal end of the elongate member and configured to be disposed at least partially within a bladder of the patient.

5. The urinary stent ofclaim 1, further comprising a tether coupled to each of the first and second arms for moving the first and second arms towards each other into the collapsed configuration.

6. A urinary stent, comprising:

an elongate member defining a lumen extending from a proximal end to a distal end of the elongate member, the proximal end comprising a proximal tip configured to be disposed within a prostatic portion of a urethra of a patient, the proximal end comprising a first arm and a second arm disposed opposite the first arm, the first and second arms defining an opening at the proximal tip of the proximal end, the opening in fluid communication with the lumen, the first and second arms being biased in an expanded configuration in which the opening has a first diameter that is substantially equal to an outer diameter of the remaining portion of the elongate member, and movable into a collapsed configuration in which the diameter of the opening is smaller than the outer diameter of the remaining portion of the elongate member; and

a second portion extending from the distal end of the elongate member and configured to be disposed at least partially within a bladder of the patient.

7. The urinary stent ofclaim 6 wherein the collapsed configuration forms a frusto-conical shape terminating at the proximal tip of the proximal end of the elongate member.

8. The urinary stent ofclaim 6 wherein the first and second arms are formed monolithically with the elongate member.

9. The urinary stent ofclaim 6 wherein the second portion has a collapsed configuration for insertion into the bladder, and an expanded configuration for retaining the second portion within the bladder.

10. The urinary stent ofclaim 6, further comprising a tether coupled to each of the first and second arms for moving the first and second arms towards each other into the collapsed configuration.

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